THE VIPER, OR ADDER. 71 



The poison apparatus of the Viper (see woodcut at 

 the head of this chapter) consists of the gland in 

 which it is secreted, the duct or canal along which 

 it travels, and the fang by means of which it is 

 injected. The gland is placed at the side of the 

 head (a), and consists of an assemblage of lobes. 

 The substance is soft and yellow, with a spongy 

 appearance. The duct or canal through which the 

 poison is conveyed to the fang is a narrow cylindrical 

 tube (b), swelling in the centre of its course into a 

 kind of reservoir, and terminating at the base of the 

 fang (c). This latter is a tooth in the form of a tube, 

 much longer than the other teeth, and curved (d). 

 It is placed in the upper jaw, one on each side of 

 the mouth. Behind these are the similarly shaped, 

 but smaller, fangs of replacement. On the outer 

 surface of the fang, near the apex, is an elongated 

 opening or slit (e), from which a canal passes through 

 the hollow in the interior of the tooth and is united 

 to the duct which communicates with the poison- 

 gland. These fangs fall backwards, and lie concealed 

 in a groove of the gum when not in use. 



The following elaborate description of the mode by 

 which the Viper wounds and envenoms its prey 

 scarcely leaves anything to be desired : — " When a 

 Viper is struck, it first coils itself up, leaving its 

 head in the centre or at the summit of the coil, and 

 drawn a little back, as if for the purpose of recon- 



